package com.macro.mall.tiny.common.utils;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class JwtTokenUtil {
    private static final Logger LOGGER = LoggerFactory.getLogger(JwtTokenUtil.class);

    private static final String CLAIM_KEY_USERNAME = "sub";

    private static final String CLAIM_KEY_CREATED = "created";
    @Value("${jwt.secret}")
    private String secret;
    @Value("${jwt.expiration}")
    private Long expiration;


    //根据负载生成JWT TOKEN
    private String generateToken(Map<String, Object> claims){
        return Jwts.builder()
                .setClaims(claims)
                .setExpiration(generateExpirationDate())
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }


    //从token中获取JWT的负载、
    private Claims getClaimsFromToken(String token) {
        Claims claims = null;
        try {
        claims = Jwts.parser()
                .setSigningKey(secret)
                .parseClaimsJws(token)
                .getBody();
        } catch (Exception e) {
            LOGGER.info("JWT格式验证失败:{}",token);
        }
        return claims;

    }

    //生成token的过期时间
    private Date generateExpirationDate () {
        return new Date(System.currentTimeMillis() + expiration * 1000);
    }

    //验证token是否还有效
    public boolean validateToken(String token, UserDetails userDetails) {
        String username = getUserNameFromToken(token);
        return username.equals(userDetails.getUsername()) && !isTokenExpired(token);
    }


    //判断token是否生效
    private boolean isTokenExpired(String token) {
        Date exprireDate = getExpiredDateFromToken(token);
        return exprireDate.before(new Date());
    }

    //从token中获取过期时间
    private Date getExpiredDateFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.getExpiration();
    }



    //从token中获取用户登录用户名
    public String getUserNameFromToken(String token) {
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        }catch (Exception e) {
            username = null;
        }
        return username;
    }

    //根据用户信息生成token
    public String generateToken(UserDetails userDetails) {
        Map<String,Object> claims = new HashMap<>();
        claims.put(CLAIM_KEY_USERNAME, userDetails.getUsername());
        claims.put(CLAIM_KEY_CREATED, new Date());
        return generateToken(claims);
    }

    //判断token是否可以被刷新
    public boolean canRefresh(String token) {
        return !isTokenExpired(token);
    }

    //刷洗token
    public String refreshToken(String token) {
        Claims claims = getClaimsFromToken(token);
        claims.put(CLAIM_KEY_CREATED, new Date());
        return generateToken(claims);
    }
}
